Simple Interest
Math MCQs

Question :    Calculate the amount due if Patricia borrowed a sum of $3150 at 6% simple interest for 3 years.

Correct Answer  $3717

Solution & Explanation

Solution

Given,

Principal (P) = $3150

Rate of Simple Interest (SI) = 6%

Time (t) = 3 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% per annum.

Method (1) Using Formula

Calculation of Simple Interest

Formula to Calculate Simple Interest

Simple Interest (SI) = Principal × Rate × Time

Thus, Simple Interest (SI) = $3150 × 6% × 3

= $3150 ×⁶/₁₀₀ × 3

= ^{3150 × 6 × 3}/₁₀₀

= ^{18900 × 3}/₁₀₀

= ⁵⁶⁷⁰⁰/₁₀₀

= $567

Thus, Simple Interest = $567

Calculation of Amount

The total money paid to the lender by a borrower is called the Amount.

In other words, sum of priciple and interest is called the Amount.

Formula to Calculate the Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $567

= $3717

Thus, Amount to be paid = $3717 Answer

Method (2)

Calculation of Amount when Principal, Rate of Simple Interest and Time are given

Calculation of Amount directly using Principal, SI, and Time

Formula to calculate the Amount

Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)

⇒ A = P + PRT

Here in the question, P = $3150

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 3 years

Thus, Amount (A)

= $3150 + ($3150 × 6% × 3)

= $3150 + ($3150 ×⁶/₁₀₀ × 3)

= $3150 + (^{3150 × 6 × 3}/₁₀₀)

= $3150 + (^{18900 × 3}/₁₀₀)

= $3150 + (⁵⁶⁷⁰⁰/₁₀₀)

= $3150 + $567 = $3717

Thus, Amount (A) to be paid = $3717 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $3150, the simple interest in 1 year

= ⁶/₁₀₀ × 3150

= ^{6 × 3150}/₁₀₀

= ¹⁸⁹⁰⁰/₁₀₀ = $189

Thus, simple interest for 1 year = $189

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $189 × 3 = $567

Thus, Simple Interest (SI) = $567

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $567

= $3717

Thus, Amount to be paid = $3717 Answer

Similar Questions

(1) What amount does William have to pay after 5 years if he takes a loan of $3500 at 8% simple interest?

(2) Calculate the amount due if Joseph borrowed a sum of $3700 at 5% simple interest for 3 years.

(3) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 7% simple interest.

(4) How much loan did Nancy borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6765 to clear it?

(5) Mark took a loan of $6800 at the rate of 8% simple interest per annum. If he paid an amount of $10064 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 3% simple interest.

(7) Find the amount to be paid if Susan borrowed a sum of $5650 at 7% simple interest for 8 years.

(8) Charles took a loan of $5800 at the rate of 7% simple interest per annum. If he paid an amount of $9860 to clear the loan, then find the time period of the loan.

(9) What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 2% simple interest?

(10) What amount does James have to pay after 6 years if he takes a loan of $3000 at 7% simple interest?